Pharmacologic class: Serotonin receptor antagonist
Therapeutic class: Agent for irritable bowel syndrome
Pregnancy risk category B
FDA Box Warning
• Infrequent but serious GI problems have occurred, resulting in hospitalization and, rarely, blood transfusions, surgery, and death.
• Only physicians enrolled in Glaxo-SmithKline's Prescribing Program for Lotronex should prescribe Lotronex.
• Drug is indicated only for women with severe, diarrhea-predominant irritable bowel syndrome who don't respond adequately to conventional therapy. Patient must read and sign agreement before receiving initial prescription.
• Discontinue immediately if patient develops constipation or ischemic colitis symptoms. Don't resume therapy in patients who developed ischemic colitis. Patients with resolved constipation should resume only on advice of physician.
Inhibits activation of nonselective cation channels, resulting in modulation of enteric nervous system
Tablets: 0.5 mg, 1 mg
Indications and dosages
➣ Women with severe, diarrhea-predominant irritable bowel syndrome (IBS) who have chronic symptoms not caused by anatomic or biochemical abnormalities and who are unresponsive to conventional therapy
Adult women: Initially, 0.5 mg P.O. b.i.d. If after 4 weeks dose is well tolerated but doesn't adequately control IBS, may increase to 1 mg P.O. b.i.d.; therapy should be discontinued in patients not responding to 1 mg P.O. b.i.d. after 4 weeks.
• Concurrent use of fluvoxamine
• Severe hepatic impairment
• Current constipation or history of chronic or severe constipation
• History of complications related to constipation
• History of intestinal obstruction, stricture, toxic megacolon, GI perforation, or adhesion
• History of ischemic colitis, impaired intestinal circulation, thrombophlebitis, or hypercoagulable state
• Current Crohn's disease or ulcerative colitis, active diverticulitis, or history of these disorders
• Inability to understand or comply with patient-physician agreement for drug
Use cautiously in:
• hepatic insufficiency
• moderate CYP/A2 inhibitors, such as quinolone antibiotics and cimetidine (avoid use)
• elderly patients
• pregnant or breastfeeding patients
☞ Before administering, know that drug is approved with the following marketing restrictions: Ensure that patient understands that drug has serious risks, patient reads and signs patient-physician agreement, and patient follows directions in accompanying medication guide.
• Know that anatomical and biochemical abnormalities of GI tract should be ruled out before drug therapy starts.
• Give with or without food.
☞ Don't administer drug if patient is constipated.
☞ Stop therapy immediately if patient develops constipation or signs or symptoms of ischemic colitis.
CNS: anxiety, malaise
CV: increased blood pressure, extrasystoles, tachyarrhythmias, arrhythmias
GI: nausea; constipation; GI pain, discomfort, or spasms; abdominal distention; regurgitation or gastroesophageal reflux; hemorrhoids; decreased salivation; dyspepsia; ischemic colitis; GI perforation; small-bowel mesenteric ischemia
GU: urinary frequency
Respiratory: breathing disorders
Skin: sweating, urticaria
Other: fatigue, cramps, disturbed temperature regulation
Drug-drug. CYP450 inducers or inhibitors: altered alosetron clearance
Fluvoxamine: increased alosetron concentration and half-life
Drug-diagnostic tests. Blood glucose, calcium, phosphate: increased or decreased level
☞ Monitor patient closely for adverse reactions, especially such GI reactions as constipation and signs or symptoms of ischemic colitis.
☞ Make sure patient knows about drug's marketing restrictions, which stipulate that she understands drug has serious risks, that she reads and signs patient-physician agreement, and that she follows directions in accompanying medication guide.
• Tell patient to take drug exactly as prescribed, with or without food.
☞ Instruct patient to contact prescriber immediately if she develops constipation or symptoms of insufficient blood flow to bowel (such as new or worsening pain in bowels or bloody bowel movements).
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.
ClassificationTherapeutic: anti irritable bowel syndrome agents
Pharmacologic: five ht3 antagonists
Time/action profile (pain/discomfort, diarrhea)
|PO||within 1–2 wk||up to 6 wk||1 wk†|
Adverse Reactions/Side Effects
- acute ischemic colitis (life-threatening)
- toxic megacolon (life-threatening)
- constipation (most frequent)
- abdominal discomfort
- abdominal distention
- GI viral infections
- regurgitation or reflux
Drug-Drug interactionFluvoxamine can ↑ levels; concurrent use contraindicated).Amiodarone, cimetidine, ciprofloxacin, clarithromycin, itraconazole, ketoconazole, ofloxacin, protease inhibitors, telithromycin, and voriconazole may ↑ levels; use concomitantly with caution.
- Monitor patient for signs of constipation or ischemic colitis (new or worsening abdominal pain, bloody diarrhea, blood in stool) throughout therapy. Patients should not start taking alosetron if they are constipated.
- Discontinue therapy immediately if patient develops constipation or signs/symptoms of ischemic colitis.
Potential Nursing DiagnosesDiarrhea (Indications)
Risk for constipation (Side Effects)
Deficient knowledge, related to medication regimen (Patient/Family Teaching)
- Do not confuse Lotronex with Protonix.
- Alosetron should only be prescribed by physicians enrolled in GlaxoSmithKline’s Prescribing Program for Alosetron.
- Oral: Administer 0.5 mg twice daily for 4 wk. If constipation occurs after initiation of therapy, discontinue until constipation resolves, then restart at 0.5 mg once daily (if constipation recurs at this dose, discontinue therapy). If IBS symptoms are not controlled after 4 wk, no constipation has occurred and patient tolerates either 0.5 mg once or twice daily, dose may be increased to 1 mg twice daily. If symptoms are not controlled after 4 wk of 1 mg twice, discontinue alosetron.
- Can be administered with or without food; however, administration with food may decrease absorption by 25%.
- Instruct patient to take alosetron exactly as directed. If a dose is missed, skip the dose and return to regular schedule; do not double doses. Counsel patients about the risks and benefits of alosetron and the impact of IBS symptoms on their life. Patients should read the Medication Guide before starting alosetron and each time they refill their prescription. The Patient-Physician Agreement should be signed, with the original in the patient’s chart and a copy to the patient, prior to initiating therapy.
- Caution patient to stop taking alosetron and report constipation or signs of ischemic colitis to health care professional immediately. Immediately contact health care professional again if constipation does not resolve after discontinuation of alosetron. Alosetron should be resumed only after constipation has resolved and on the advice of their health care professional. Treatment with alosetron should not be resumed in patients who develop ischemic colitis.
- Increased colonic transit time without affecting orocecal transit time resulting in decreased pain, discomfort, and diarrhea associated with IBS.